The invention concerns a film laminated plastic moulding which includes a rigid plastic support and a film which is joined to at least one surface area of the plastic support and where the film exhibits a fold round the plastic support on at least one edge, as well as a process and device for its manufacture.
Many large surface plastic mouldings, e.g. panelling on the inside of doors or seat back panelling for automobiles are covered completely or in certain areas with a decorative film on visual grounds. The decorative film must be applied with a "fold", which preferably extends to 180.degree., around the edges of the plastic moulding. PVC covering fabrics with PP foam or else knitted fabrics based on PET with PP foam are particularly worth considering. The material of the rigid support consists predominantly of PP (possibly modified with talc).
Known plastic mouldings of the type mentioned at the start are manufactured in the following manner: first of all the rigid plastic support is injected into a suitable press. The main surfaces of the completed plastic support are then covered with the film in which first of all a film edge projects at the margins. These edges--which are if needed supplied with suitable incisions on the bends--are finally placed around the plastic support and stuck on by hand by which means the necessary fold is formed. This known manufacturing process is not only dear since it requires manual labour. It is furthermore also no longer desirable on environmental grounds on account of the adhesive which is used.
It is therefore the task of the present invention to create a film laminated plastic moulding of the type specified at the start which can be manufactured economically and with a sorted plastic without the use of an adhesive.
This task is solved according to the invention in that the plastic support is a body that is pressed into the fold of the film in the melt and then solidified.
Thus, according to the invention, the manufacture of the film laminated plastic moulding proceeds quite differently from what was the case in the Prior Art: first of all the plastic film is brought into that form which it adopts--inclusive of its fold--in the finished plastic moulding. Then the material of the plastic support is applied in a suitable manner to the film thus prepared, pressed into the area of the fold and thus incidentally also brought into that form which the plastic moulding should finally possess. The preforming of the film required in this connection may easily be effected; the use of an adhesive is rendered superfluous by the later application of the melt of the plastic support on the film; sorted plastics can be used.
In many cases plastic mouldings of the type which is here of interest include several fields which are separated from one another by separation seams. The surfaces of the individual fields are then fashioned differently. For example one of these fields can later be painted whilst one or several of these fields are possibly provided with different films on the visible side.
A plastic moulding of this type can also include a foam padding arranged between the film and the plastic support.
It is further the task of the invention to indicate a process for the manufacture of a film laminated plastic moulding of the type mentioned at the start which can be carried out economically and without the use of adhesives.
This process distinguishes itself in that
a) the film is first brought into a form which already corresponds to that which it has in the finished plastic moulding including the fold; PA1 b) only then is the melt of the material which forms the plastic support applied to the ready formed film and its fold and allowed to solidify there. PA1 a) the foam padding is fixed to the film; PA1 b) the foam padding is temporarily reinforced by the injection of a gas during the introduction of the melt of the material forming the plastic support. PA1 a) the film is brought into approximately its final form in a first deep draw step; PA1 b) the pre-drawn film is introduced into a mould cavity which corresponds to the shape of the plastic moulding which is to be manufactured and in this is brought into the final shape by application on to the mould cavity wall before the melt of the material forming the plastic support is applied. PA1 a) a matrix in which a mould cavity is formed which partially imitates the shape of the plastic moulding which is to be manufactured; PA1 b) means which serve for the application of the film inserted into the mould cavity onto the wall of the mould cavity; PA1 c) a heating apparatus with which an edge of the film which projects over the mould cavity of the matrix may be heated; PA1 d) at least one outer slide whose inner edge reproduces the outer half of the edge of the plastic moulding which is to be manufactured and which may be transported laterally from outside against the projecting edge of the film; PA1 e) at least one inner slide, whose outer edge reproduces the inner half of the edge of the plastic moulding which is to be manufactured and which may be transported laterally from inside against the projecting edge of the film; PA1 f) at least one nozzle via which the melt of the material forming the plastic support can be applied to the film laid on the mould cavity of the matrix; PA1 g) a compression moulding apparatus with which the melt can be pressed into the fold of the film and the plastic support can be brought into its final shape lying at least partly on the film. PA1 The lateral movement of the inner slide should usefully be accompanied by a movement directed perpendicular to it onto the free rim of the film edge. The bending back of the film edge into an fold is facilitated by this combined motion. PA1 a) a punch is provided which may be driven through the matrix into the mould cavity and which outlines the shape of the separation seam; PA1 b) on a pressure plate which forms the moulding apparatus a multiplicity of protruding lugs are formed parallel to the course of the punch against which the punch may be laid.
The advantages of the process according to the invention correspond in summary to those explained above for the plastic moulding according to the invention.
According to a preferred implementation, the process according to the invention distinguishes itself in that one or more melt cakes of the melt are firstly applied in a laminar flow process to the already formed film and moulded in a subsequent compression process into the final plastic support. The introduction of the melt cake takes place through this laminar flow process with the least possible application of force to the film which should of course not be disturbed any more during this course of events.
As has already been mentioned, certain plastic mouldings should have integrated foam padding. For manufacture of plastic mouldings of this type, an implementation of the process according to the invention is recommended in which
By this means a situation is arrived at in which the melt which is applied to the foam padding and which surrounds it does not, during the moulding into the final form of the plastic support, compress the foam padding by which this would lose its pliability. The gas introduced in to the foam padding on the contrary builds up a counter pressure which opposes the pressure of the melt in the moulding process and prevents any compression of the foam padding. Once the moulding process is complete and the plastic material is rigid, the gas can again be released from the foam padding through which it regains its elasticity.
Inasmuch as the plastic moulding which is to be manufactured exhibits a strongly profiled surface, an implementation of the process is recommended in which
The first step in the process thus takes place in a separate mould whilst the second step in the process takes place in that device in which the final plastic moulding ensues through injection of the plastic carrier.
It is further the task of the present invention to create a device with which the plastic moulding mentioned at the start can be manufactured economically and without the use of adhesives.
This task is solved according to the invention in that the device includes:
Central elements of the device according to the invention are thus the outer and inner slides which together preform the at first unshaped film edge which projects over the mould cavity of the matrix into a fold which corresponds to the final shape of the fold in the completed plastic moulding. The heating apparatus of the device according to the invention thus heats the projecting edge in such a way that it can easily be brought into the desired shape by the two slides.
The means for laying the film onto the mould cavity in the matrix preferably include a vacuum apparatus with channels which open out onto the mould cavity. When the vacuum apparatus starts functioning, the space between the inserted film and the wall of the mould cavity is evacuated through which the film lies tightly on the wall of the mould cavity.
It is correspondingly also recommended that the vacuum apparatus be joined to the area of the film fold via the vertical and horizontal partition surfaces between the outer slide and the inner slide and the parts adjoining them. In this manner the projecting edge of the film which has already been preformed into the fold by the outer and inner slides is fully applied onto the suitably contoured edges of outer and inner slides with the help of the partial vacuum produced by the vacuum apparatus.
Advantageously, the nozzle should be a heated and controlled needle valve nozzle. Needle valve nozzles of this type are in themselves already known and therefore need not be further explained here.
In a preferred implementation form of the invention, the heating apparatus is formed as a movable heating frame with a heating coil which may be transported into a position which is parallel to the inner surface of the film edge which protrudes over the mould cavity of the matrix. The heating apparatus is only brought into this position for a short time and then removed from the area of the film edge at a suitable time in coordination with the movements of the outer and inner slides.
The movement of the outer slide can usefully be controlled in that the outer slide may be moved by at least one guide pin which is fixed diagonal to a vertically moving press top part and which penetrates a through bore in the outer slide which runs diagonally at the same angle. The vertical movement of the press top part with which the closing of further mould parts is effected is converted in this manner into a corresponding lateral movement of the outer slide which is correlated in terms of time.
The moulding apparatus can include a pressure plate which is arranged movably in a recess of a mould ring whereby the mould ring is itself movable and imitates part of the shape of the plastic moulding to be completed with its outer surface which faces the mould recess. In this case after closing of the outer and inner slides the mould ring is first of all displaced in the direction of the matrix such that together with the matrix and the corresponding outer zones of the outer and inner slides it already defines to a great extent the finished form of the plastic moulding to be manufactured, although however the area of the pressure plate is still excluded which will only be pushed forward in a further function step. The melt cake which has been applied-to the film is then pressed by this into the mould and thereby in particular also into the fold of the film by which the mould in which the rigid plastic support ensues is completely closed.
For manufacture of plastic mouldings with integrated foam padding an implementation is recommended in which an injection needle is provided which may be transported into the mould cavity and via which gas under pressure can be supplied to foam padding which has been applied to the film. The reason for this measure has already been explained above.
For manufacture of film laminated plastic mouldings which include several fields which are separated from one another by separation seams, an implementation of the device according to the invention is preferably used which distinguishes itself in that
The punch thus on the one hand stamps out the desired clear-cut separation seams and on the other hand serves in the final phase of the moulding process for the plastic support, and particularly during its solidification, for clipping of the edge of the film located here to the pressure plate in cooperation with the lugs.
Additionally, a device according to the invention can include a laterally transportable slide which imitates with an area of its outer contour a hook like projection which serves for clipping of the plastic moulding.
The laterally movable slide may additionally be transported vertical together with at least one ejector. It may then take over the function of an ejector.
A useful implementation provides that the laterally movable slide includes a punch which is introduced into an essentially vertically movable part such that the vertical motion of this part is converted into a lateral movement of the slide.